Jumat, 29 Juni 2012

Origami (in English)

Origami cranes

Origami (折り紙, from ori meaning "folding", and kami meaning "paper"; kami changes to gami due to rendaku) is the traditional Japanese art
of paper folding, which started in the 17th century AD at the latest
and was popularized outside of Japan in the mid-1900s. It has since then
evolved into a modern art form. The goal of this art is to transform a
flat sheet of paper into a finished sculpture through folding and
sculpting techniques, and as such the use of cuts or glue are not
considered to be origami. Paper cutting and gluing is usually considered
kirigami.

The folding of an Origami crane

The number of basic origami folds
is small, but they can be combined in a variety of ways to make
intricate designs. The best known origami model is probably the Japanese
paper crane. In general, these designs begin with a square sheet of paper whose sides may be different colors or prints. Traditional Japanese origami, which has been practiced since the Edo era
(1603–1867), has often been less strict about these conventions,
sometimes cutting the paper or using nonsquare shapes to start with.The principles of origami are also being used in stents, packaging and other engineering structures.

History

Swan by Akira Yoshizawa, the father of modern origami techniques.

Japanese school children dedicate their contribution of Thousand origami cranes at the Sadako Sasaki memorial in Hiroshima.

There is much speculation about the origin of Origami. While Japan
seems to have had the most extensive tradition, there is evidence of an
independent tradition of paperfolding in China,
as well as in Germany, Italy and Spain among other places. However,
because of the problems associated with preserving origami, there is
very little direct evidence of its age or origins, aside from references
in published material.In China, traditional funerals include burning folded paper, most often representations of gold nuggets (yuanbao). It is not known when this practice started, but it seems to have become popular during the Sung Dynasty (905–1125 CE). The paper folding has typically been of objects like dishes, hats or boats rather than animals or flowers.The earliest evidence of paperfolding in Europe is a picture of a small paper boat in Tractatus de sphaera mundi from 1490. There is also evidence of a cut and folded paper box from 1440. It is probable paperfolding in the west originated with the Moors much earlier, it is not known if it was independently discovered or knowledge of origami came along the silk route.In Japan, the earliest unambiguous reference to a paper model is in a short poem by Ihara Saikaku in 1680 which describes paper butterflies in a dream. Origami butterflies were used during the celebration of Shinto weddings to represent the bride and groom, so paperfolding had already become a significant aspect of Japanese ceremony by the Heian period (794–1185) of Japanese history, enough that the reference in this poem would be recognized. Samurai warriors would exchange gifts adorned with noshi, a sort of good luck token made of folded strips of paper.In the early 1900s, Akira Yoshizawa, Kosho Uchiyama,
and others began creating and recording original origami works. Akira
Yoshizawa in particular was responsible for a number of innovations,
such as wet-folding and the Yoshizawa–Randlett diagramming system, and his work inspired a renaissance of the art form. During the 1980s a number of folders started systematically studying
the mathematical properties of folded forms, which led to a steady
increase in the complexity of origami models, which continued well into
the 1990s, after which some designers started returning to simpler
forms.

Techniques and materials

Techniques

A crane and papers of the same size used to fold it

Many origami books begin with a description of basic origami techniques
which are used to construct the models. These include simple diagrams
of basic folds like valley and mountain folds, pleats, reverse folds,
squash folds, and sinks. There are also standard named bases which are
used in a wide variety of models, for instance the bird base is an
intermediate stage in the construction of the flapping bird. Additional bases are the preliminary base (square base), fish base, waterbomb base, and the frog base.

Origami paper

Almost any laminar material can be used for folding; the only requirement is that it should hold a crease.

Origami paper, often referred to as "kami" (Japanese for paper), is
sold in prepackaged squares of various sizes ranging from 2.5 cm to
25 cm or more. It is commonly colored on one side and white on the
other; however, dual coloured and patterned versions exist and can be
used effectively for color-changed models. Origami paper weighs slightly
less than copy paper, making it suitable for a wider range of models.Normal copy paper with weights of 70–90 g/m2 can be used for simple folds, such as the crane and waterbomb. Heavier weight papers of (19–24&nb 100 g/m2 (approx. 25 lb) or more can be wet-folded. This technique allows for a more rounded sculpting of the model, which becomes rigid and sturdy when it is dry.Foil-backed paper, just as its name implies, is a sheet of thin foil
glued to a sheet of thin paper. Related to this is tissue foil, which is
made by gluing a thin piece of tissue paper to kitchen aluminium foil.
A second piece of tissue can be glued onto the reverse side to produce a
tissue/foil/tissue sandwich. Foil-backed paper is available
commercially, but not tissue foil; it must be handmade. Both types of
foil materials are suitable for complex models.Washi (和紙)
is the traditional origami paper used in Japan. Washi is generally
tougher than ordinary paper made from wood pulp, and is used in many
traditional arts. Washi is commonly made using fibres from the bark of
the gampi tree, the mitsumata shrub (Edgeworthia papyrifera), or the paper mulberry but also can be made using bamboo, hemp, rice, and wheat.Artisan papers such as unryu, lokta, hanji, gampi, kozo, saa, and
abaca have long fibres and are often extremely strong. As these papers
are floppy to start with, they are often backcoated or resized with methylcellulose
or wheat paste before folding. Also, these papers are extremely thin
and compressible, allowing for thin, narrowed limbs as in the case of
insect models.Paper money from various countries is also popular to create origami
with; this is known variously as Dollar Origami, Orikane, and Money
Origami.

Tools

It is common to fold using a flat surface but some folders like doing
it in the air with no tools especially when displaying the folding.
Many folders believe no tool should be used when folding. However a
couple of tools can help especially with the more complex models. For
instance a bone folder allows sharp creases to be made in the paper easily, paper clips can act as extra pairs of fingers, and tweezers can be used to make small folds. When making complex models from origami crease patterns, it can help to use a ruler and ballpoint embosser
to score the creases. Completed models can be sprayed so they keep
their shape better, and of course a spray is needed when wet folding.

Types of origami

Action origami

Origami not only covers still-life, there are also moving objects;
Origami can move in clever ways. Action origami includes origami that
flies, requires inflation to complete, or, when complete, uses the kinetic energy
of a person's hands, applied at a certain region on the model, to move
another flap or limb. Some argue that, strictly speaking, only the
latter is really "recognized" as action origami. Action origami, first
appearing with the traditional Japanese flapping bird, is quite common.
One example is Robert Lang's
instrumentalists; when the figures' heads are pulled away from their
bodies, their hands will move, resembling the playing of music.

Modular origami

A stellated icosahedron made from custom papers

Modular origami consists of putting a number of similar pieces
together to form a complete model. Normally the individual pieces are
simple but the final assembly may be tricky. Many of the modular origami
models are decorative balls like kusudama, the technique differs though in that kusudama allows the pieces to be put together using thread or glue.Chinese paper folding
includes a style called 3D origami where large numbers of pieces are
put together to make elaborate models. Sometimes paper money is used for
the modules. This style originated from some Chinese refugees while
they were detained in America and is also called Golden Venture folding from the ship they came on.

Wet-folding

Wet-folding is an origami technique for producing models with gentle
curves rather than geometric straight folds and flat surfaces. The paper
is dampened so it can be moulded easily, the final model keeps its
shape when it dries. It can be used, for instance, to produce very
natural looking animal models. Size, an adhesive that is crisp and hard
when dry, but dissolves in water when wet and becoming soft and
flexible, is often applied to the paper either at the pulp stage while
the paper is being formed, or on the surface of a ready sheet of paper.
The latter method is called external sizing and most commonly uses
Methylcellulose, or MC, paste, or various plant starches.

Pureland origami

Pureland origami is origami with the restriction that only one fold
may be done at a time, more complex folds like reverse folds are not
allowed, and all folds have straightforward locations. It was developed
by John Smith in the 1970s to help inexperienced folders or those with
limited motor skills. Some designers also like the challenge of creating
good models within the very strict constraints.

Origami tessellations

This branch of origami is one that has grown in popularity recently. A tessellation
is a collection of figures filling a plane with no gaps or overlaps. In
origami tessellations, pleats are used to connect molecules such as
twist folds together in a repeating fashion.During the 1960s, Shuzo Fujimoto was the first to explore twist fold
tessellations in any systematic way, coming up with dozens of patterns
and establishing the genre in the origami mainstream. Around the same
time period, Ron Resch patented some tessellation patterns as part of
his explorations into kinetic sculpture and developable surfaces,
although his work was not known by the origami community until the
1980s. Chris Palmer is an artist who has extensively explored
tessellations after seeing the Zilij patterns in the Alhambra, and has found ways to create detailed origami tessellations out of silk. Robert Lang
and Alex Bateman are two designers who use computer programs to create
origami tessellations. The first American book on origami tessellations
was just published by Eric Gjerde and the field has been expanding
rapidly. There are numerous origami tessellation artists including Chris
Palmer (U.S.), Eric Gjerde (U.S.), Polly Verity (Scotland), Joel Cooper
(U.S.), Christine Edison (U.S.), Ray Schamp (U.S.), Roberto Gretter
(Italy), Goran Konjevod (U.S.),and Christiane Bettens (Switzerland) that
are showing works that are both geometric and representational.

Kirigami

Kirigami is a Japanese term for paper cutting. Cutting was often used
in traditional Japanese origami, but modern innovations in technique
have made the use of cuts unnecessary. Most origami designers no longer
consider models with cuts to be origami, instead using the term Kirigami
to describe them. This change in attitude occurred during the 1960s and
70s, so early origami books often use cuts, but for the most part they
have disappeared from the modern origami repertoire; most modern books
don't even mention cutting.

Moneygami

Moneygami is a form of Origami where currency notes are used instead of paper to create Origami art.

Mathematics and technical origami

Mathematics and practical applications

Spring Into Action, designed by Jeff Beynon, made from a single rectangular piece of paper.

The practice and study of origami encapsulates several subjects of mathematical interest. For instance, the problem of flat-foldability (whether a crease pattern can be folded into a 2-dimensional model) has been a topic of considerable mathematical study.

A number of technological advances have come from insights obtained
through paper folding. For example, techniques have been developed for
the deployment of car airbags and stent implants from a folded position.The problem of rigid origami
("if we replaced the paper with sheet metal and had hinges in place of
the crease lines, could we still fold the model?") has great practical
importance. For example, the Miura map fold is a rigid fold that has been used to deploy large solar panel arrays for space satellites.Origami can be used to construct various geometrical designs not possible with compass and straightedge constructions. For instance paper folding may be used for angle trisection and doubling the cube.There are plans for an origami airplane to be launched from space.
A prototype passed a durability test in a wind tunnel on March 2008,
and Japan's space agency adopted it for feasibility studies.

Hercules Beetle by Robert Lang.

Technical origami

Technical origami, also known as origami sekkei (折り紙設計),
is a field of origami that has developed almost hand-in-hand with the
field of mathematical origami. In the early days of origami, development
of new designs was largely a mix of trial-and-error, luck and
serendipity. With advances in origami mathematics however, the basic
structure of a new origami model can be theoretically plotted out on
paper before any actual folding even occurs. This method of origami
design was developed by Robert Lang, Meguro Toshiyuki
and others, and allows for the creation of extremely complex
multi-limbed models such as many-legged centipedes, human figures with a
full complement of fingers and toes, and the like.The main starting point for such technical designs is the crease pattern
(often abbreviated as CP), which is essentially the layout of the
creases required to form the final model. Although not intended as a
substitute for diagrams, folding from crease patterns is starting to
gain in popularity, partly because of the challenge of being able to
'crack' the pattern, and also partly because the crease pattern is often
the only resource available to fold a given model, should the designer
choose not to produce diagrams. Still, there are many cases in which
designers wish to sequence the steps of their models but lack the means
to design clear diagrams. Such origamists occasionally resort to the sequenced crease pattern
(SCP) which is a set of crease patterns showing the creases up to each
respective fold. The SCP eliminates the need for diagramming programs or
artistic ability while maintaining the step-by-step process for other
folders to see. Another name for the sequenced crease pattern is the
progressive crease pattern (PCP).Paradoxically enough, when origami designers come up with a crease
pattern for a new design, the majority of the smaller creases are
relatively unimportant and added only towards the completion of the
crease pattern. What is more important is the allocation of regions of
the paper and how these are mapped to the structure of the object being
designed. For a specific class of origami bases known as 'uniaxial
bases', the pattern of allocations is referred to as the
'circle-packing'. Using optimization algorithms, a circle-packing figure
can be computed for any uniaxial base of arbitrary complexity. Once
this figure is computed, the creases which are then used to obtain the
base structure can be added. This is not a unique mathematical process,
hence it is possible for two designs to have the same circle-packing,
and yet different crease pattern structures.As a circle encloses the maximum amount of area for a given
perimeter, circle packing allows for maximum efficiency in terms of
paper usage. However, other polygonal shapes can be used to solve the
packing problem as well. The use of polygonal shapes other than circles
is often motivated by the desire to find easily locatable creases (such
as multiples of 22.5 degrees) and hence an easier folding sequence as
well. One popular offshoot of the circle packing method is box-pleating,
where squares are used instead of circles. As a result, the crease
pattern that arises from this method contains only 45 and 90 degree
angles, which makes for easier folding.

Origami-related computer programs

Doodle: used to diagram all the steps and figures involved in the creation of a figure.

OriPa: a program for drawing up crease patterns. Allows one to see what a crease pattern looks like when folded.

Ethics

Copyright in origami designs and the use of models has become an
increasingly important issue as the internet has made the sale and
distribution of pirated designs very easy. It is considered good ethics to always credit the original artist and
the folder when displaying origami models. All commercial rights to
designs and models are typically reserved by origami artists. Normally a
person who folds a model using a legally obtained design can publicly
display the model unless such rights are specifically reserved, however
folding a design for money or commercial use of a photo for instance
would require consent.

Gallery

These pictures show examples of various types of origami. Click the image to enlarge.

Smart Waterbomb using circular paper and curved folds

An example of origami bonsai

Kawasaki cube, an example of an iso-area model

Two examples of modular origami

Kawasaki rose using the twist fold devised by Toshikazu Kawasaki. The calyx is made separately.